This invention relates to a signal receiving coil device for use in a magnetic resonance imaging apparatus (hereinafter referred to as the "MRI apparatus"). More in particular, it relates to a signal receiving coil device having flexibility such that it can be brought into close contact with a patient.
The MRI apparatus displays a tomographic image by placing a patient in a strong and homogeneous static magnetic field generated by a magnet for generating the static magnetic field, applying a high-frequency magnetic field and a gradient magnetic field to the patient in accordance with a predetermined pulse sequence so as to allow a nuclear spin of a predetermined section of the patient to cause nuclear magnetic resonance (hereinafter referred to as "NMR"), detecting the resulting NMR signals, and subjecting the detection signals to two-dimensional Fourier transform etc. for image reconstruction.
Detection of the NMR signals is effected by placing an high-frequency signal receiving coil in the proximity of the patient, and conventional detection methods include a method which receives unidirectional NMR signals by the use of a set of coil units such as solenoid coil units or saddle coil units, and a method which uses two sets of coil units, arranges them in such a manner that the directions of their sensitivity cross each another at right angles, and receives bidirectional NMR signals in order to improve a signal-to-noise ratio (S/N). Since the signal receiving directions of the two coil units are orthogonal to each other in the latter, the coils are referred to as "QD" (Quadrature Detection) coil unit.
The QD coils that have been proposed so far include a QD coil unit for a horizontal magnetic field comprising the combination of a saddle coil unit with another, for example, and a QD coil unit for a vertical magnetic field comprising the combination of a solenoid coil unit with the saddle coil unit, for example.